title: In situ tissue regeneration using a novel tissue-engineered, small-caliber vascular graft without cell seeding.
abstract: OBJECTIVE
  Various types of natural and synthetic scaffolds with arterial tissue cells or differentiated stem cells have recently attracted interest as potential small-caliber vascular grafts. It was thought that the synthetic graft with the potential to promote autologous tissue regeneration without any seeding would be more practical than a seeded graft. In this study, we investigated in situ tissue regeneration in small-diameter arteries using a novel tissue-engineered biodegradable vascular graft that did not require ex vivo cell seeding.
  
  
  METHODS
  Small-caliber vascular grafts (4 mm in diameter) were fabricated by compounding a collagen microsponge with a biodegradable woven polymer tube that was constructed in a plain weave pattern with a double layer of polyglycolic acid (core) and poly-L-lactic acid (sheath) fibers. We implanted these tissue-engineered vascular grafts bilaterally into the carotid arteries of mongrel dogs (body weight, 20-25 kg). No anticoagulation regimen was used after implantation. We sacrificed the dogs 2, 4, 6, and 12 months (n = 4 in each group) after implantation and evaluated the explants histologically and biochemically.
  
  
  RESULTS
  All of the tissue-engineered vascular grafts were patent with no signs of thrombosis or aneurysm at any time. Histologic and biochemical examinations showed excellent in situ tissue regeneration with an endothelial cell monolayer, smooth muscle cells, and a reconstructed vessel wall with elastin and collagen fibers.
  
  
  CONCLUSIONS
  Our study indicated that this novel tissue-engineered vascular graft promoted in situ tissue regeneration and did not require ex vivo cell seeding, thereby conferring better patency on small-caliber vascular prostheses.
authors.affiliation: Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Takenori
authors.initials: T
authors.lastname: Yokota
authors.forename: Hajime
authors.initials: H
authors.lastname: Ichikawa
authors.forename: Goro
authors.initials: G
authors.lastname: Matsumiya
authors.forename: Toru
authors.initials: T
authors.lastname: Kuratani
authors.forename: Taichi
authors.initials: T
authors.lastname: Sakaguchi
authors.forename: Shigemitsu
authors.initials: S
authors.lastname: Iwai
authors.forename: Yukitoshi
authors.initials: Y
authors.lastname: Shirakawa
authors.forename: Kei
authors.initials: K
authors.lastname: Torikai
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Saito
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Uchimura
authors.forename: Naomasa
authors.initials: N
authors.lastname: Kawaguchi
authors.forename: Nariaki
authors.initials: N
authors.lastname: Matsuura
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Sawa
mesh_terms: D000818:Animals; D001705:Bioprosthesis; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000379:methods; D002339:Carotid Arteries / Q000473:pathology* / Q000601:surgery*; D016893:Carotid Stenosis / Q000601:surgery; D004195:Disease Models, Animal; D004285:Dogs; D006084:Graft Rejection; D006085:Graft Survival; D007150:Immunohistochemistry; D019344:Lactic Acid / Q000737:chemistry; D011091:Polyesters; D011100:Polyglycolic Acid / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011897:Random Allocation; D012038:Regeneration / Q000502:physiology*; D012680:Sensitivity and Specificity; D023822:Tissue Engineering; D014654:Vascular Patency / Q000502:physiology
chemical_list: D011091:Polyesters; D011108:Polymers; D011100:Polyglycolic Acid; D019344:Lactic Acid; C033616:poly(lactide)